The semiconductor integrated circuit (IC) industry has experienced exponential growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs.
Defect analysis is an important aspect of the IC industry. It is common for defects to occur in the substrate being fabricated, such as a wafer with one or more dies, as well as in masks used to fabricate the substrate. In light of the advanced scaling that has occurred, smaller defects become more critical, and more difficult to detect and analyze. Generally, tools such as a transmission electron microscope (TEM) or an energy-dispersing x-ray scanning electron microscope or energy dispersive X-ray spectroscopy (collectively referred to as EDX) are used for defect analysis. However, these tools often have difficulty with very small defects, and for handling background signals. Also, sample preparation for these tools are often very difficult to prepare, and sometime require destroying the item (e.g., wafer or mask) to be analyzed. Accordingly, what is needed is a method to analyze defects in a quicker and more accurate way.